Abstract
Effect of surface wettability on friction coefficient of horizontal circular pipe has been studied experimentally. We tested three cases; one is a normal glass tube(CASE 1) and the others are aluminum(CASE 2) and glass(CASE 3) tubes with super-water-repellent(SWR) wall. For CASE 2 drag reduction was observed by 20% compared with the others in single-phase laminar flow region, while drag coefficient of CASE 2 and 3 was increased in two-phase flow region.
